xref: /openbmc/linux/kernel/trace/Kconfig (revision e11ec2b8)
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Architectures that offer an FUNCTION_TRACER implementation should
4#  select HAVE_FUNCTION_TRACER:
5#
6
7config USER_STACKTRACE_SUPPORT
8	bool
9
10config NOP_TRACER
11	bool
12
13config HAVE_RETHOOK
14	bool
15
16config RETHOOK
17	bool
18	depends on HAVE_RETHOOK
19	help
20	  Enable generic return hooking feature. This is an internal
21	  API, which will be used by other function-entry hooking
22	  features like fprobe and kprobes.
23
24config HAVE_FUNCTION_TRACER
25	bool
26	help
27	  See Documentation/trace/ftrace-design.rst
28
29config HAVE_FUNCTION_GRAPH_TRACER
30	bool
31	help
32	  See Documentation/trace/ftrace-design.rst
33
34config HAVE_FUNCTION_GRAPH_RETVAL
35	bool
36
37config HAVE_DYNAMIC_FTRACE
38	bool
39	help
40	  See Documentation/trace/ftrace-design.rst
41
42config HAVE_DYNAMIC_FTRACE_WITH_REGS
43	bool
44
45config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
46	bool
47
48config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
49	bool
50
51config HAVE_DYNAMIC_FTRACE_WITH_ARGS
52	bool
53	help
54	 If this is set, then arguments and stack can be found from
55	 the ftrace_regs passed into the function callback regs parameter
56	 by default, even without setting the REGS flag in the ftrace_ops.
57	 This allows for use of ftrace_regs_get_argument() and
58	 ftrace_regs_get_stack_pointer().
59
60config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
61	bool
62	help
63	  If the architecture generates __patchable_function_entries sections
64	  but does not want them included in the ftrace locations.
65
66config HAVE_FTRACE_MCOUNT_RECORD
67	bool
68	help
69	  See Documentation/trace/ftrace-design.rst
70
71config HAVE_SYSCALL_TRACEPOINTS
72	bool
73	help
74	  See Documentation/trace/ftrace-design.rst
75
76config HAVE_FENTRY
77	bool
78	help
79	  Arch supports the gcc options -pg with -mfentry
80
81config HAVE_NOP_MCOUNT
82	bool
83	help
84	  Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
85
86config HAVE_OBJTOOL_MCOUNT
87	bool
88	help
89	  Arch supports objtool --mcount
90
91config HAVE_OBJTOOL_NOP_MCOUNT
92	bool
93	help
94	  Arch supports the objtool options --mcount with --mnop.
95	  An architecture can select this if it wants to enable nop'ing
96	  of ftrace locations.
97
98config HAVE_C_RECORDMCOUNT
99	bool
100	help
101	  C version of recordmcount available?
102
103config HAVE_BUILDTIME_MCOUNT_SORT
104       bool
105       help
106         An architecture selects this if it sorts the mcount_loc section
107	 at build time.
108
109config BUILDTIME_MCOUNT_SORT
110       bool
111       default y
112       depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
113       help
114         Sort the mcount_loc section at build time.
115
116config TRACER_MAX_TRACE
117	bool
118
119config TRACE_CLOCK
120	bool
121
122config RING_BUFFER
123	bool
124	select TRACE_CLOCK
125	select IRQ_WORK
126
127config EVENT_TRACING
128	select CONTEXT_SWITCH_TRACER
129	select GLOB
130	bool
131
132config CONTEXT_SWITCH_TRACER
133	bool
134
135config RING_BUFFER_ALLOW_SWAP
136	bool
137	help
138	 Allow the use of ring_buffer_swap_cpu.
139	 Adds a very slight overhead to tracing when enabled.
140
141config PREEMPTIRQ_TRACEPOINTS
142	bool
143	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
144	select TRACING
145	default y
146	help
147	  Create preempt/irq toggle tracepoints if needed, so that other parts
148	  of the kernel can use them to generate or add hooks to them.
149
150# All tracer options should select GENERIC_TRACER. For those options that are
151# enabled by all tracers (context switch and event tracer) they select TRACING.
152# This allows those options to appear when no other tracer is selected. But the
153# options do not appear when something else selects it. We need the two options
154# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
155# hiding of the automatic options.
156
157config TRACING
158	bool
159	select RING_BUFFER
160	select STACKTRACE if STACKTRACE_SUPPORT
161	select TRACEPOINTS
162	select NOP_TRACER
163	select BINARY_PRINTF
164	select EVENT_TRACING
165	select TRACE_CLOCK
166	select TASKS_RCU if PREEMPTION
167
168config GENERIC_TRACER
169	bool
170	select TRACING
171
172#
173# Minimum requirements an architecture has to meet for us to
174# be able to offer generic tracing facilities:
175#
176config TRACING_SUPPORT
177	bool
178	depends on TRACE_IRQFLAGS_SUPPORT
179	depends on STACKTRACE_SUPPORT
180	default y
181
182menuconfig FTRACE
183	bool "Tracers"
184	depends on TRACING_SUPPORT
185	default y if DEBUG_KERNEL
186	help
187	  Enable the kernel tracing infrastructure.
188
189if FTRACE
190
191config BOOTTIME_TRACING
192	bool "Boot-time Tracing support"
193	depends on TRACING
194	select BOOT_CONFIG
195	help
196	  Enable developer to setup ftrace subsystem via supplemental
197	  kernel cmdline at boot time for debugging (tracing) driver
198	  initialization and boot process.
199
200config FUNCTION_TRACER
201	bool "Kernel Function Tracer"
202	depends on HAVE_FUNCTION_TRACER
203	select KALLSYMS
204	select GENERIC_TRACER
205	select CONTEXT_SWITCH_TRACER
206	select GLOB
207	select TASKS_RCU if PREEMPTION
208	select TASKS_RUDE_RCU
209	help
210	  Enable the kernel to trace every kernel function. This is done
211	  by using a compiler feature to insert a small, 5-byte No-Operation
212	  instruction at the beginning of every kernel function, which NOP
213	  sequence is then dynamically patched into a tracer call when
214	  tracing is enabled by the administrator. If it's runtime disabled
215	  (the bootup default), then the overhead of the instructions is very
216	  small and not measurable even in micro-benchmarks (at least on
217	  x86, but may have impact on other architectures).
218
219config FUNCTION_GRAPH_TRACER
220	bool "Kernel Function Graph Tracer"
221	depends on HAVE_FUNCTION_GRAPH_TRACER
222	depends on FUNCTION_TRACER
223	depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
224	default y
225	help
226	  Enable the kernel to trace a function at both its return
227	  and its entry.
228	  Its first purpose is to trace the duration of functions and
229	  draw a call graph for each thread with some information like
230	  the return value. This is done by setting the current return
231	  address on the current task structure into a stack of calls.
232
233config FUNCTION_GRAPH_RETVAL
234	bool "Kernel Function Graph Return Value"
235	depends on HAVE_FUNCTION_GRAPH_RETVAL
236	depends on FUNCTION_GRAPH_TRACER
237	default n
238	help
239	  Support recording and printing the function return value when
240	  using function graph tracer. It can be helpful to locate functions
241	  that return errors. This feature is off by default, and you can
242	  enable it via the trace option funcgraph-retval.
243	  See Documentation/trace/ftrace.rst
244
245config DYNAMIC_FTRACE
246	bool "enable/disable function tracing dynamically"
247	depends on FUNCTION_TRACER
248	depends on HAVE_DYNAMIC_FTRACE
249	default y
250	help
251	  This option will modify all the calls to function tracing
252	  dynamically (will patch them out of the binary image and
253	  replace them with a No-Op instruction) on boot up. During
254	  compile time, a table is made of all the locations that ftrace
255	  can function trace, and this table is linked into the kernel
256	  image. When this is enabled, functions can be individually
257	  enabled, and the functions not enabled will not affect
258	  performance of the system.
259
260	  See the files in /sys/kernel/tracing:
261	    available_filter_functions
262	    set_ftrace_filter
263	    set_ftrace_notrace
264
265	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
266	  otherwise has native performance as long as no tracing is active.
267
268config DYNAMIC_FTRACE_WITH_REGS
269	def_bool y
270	depends on DYNAMIC_FTRACE
271	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
272
273config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
274	def_bool y
275	depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
276	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
277
278config DYNAMIC_FTRACE_WITH_CALL_OPS
279	def_bool y
280	depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
281
282config DYNAMIC_FTRACE_WITH_ARGS
283	def_bool y
284	depends on DYNAMIC_FTRACE
285	depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
286
287config FPROBE
288	bool "Kernel Function Probe (fprobe)"
289	depends on FUNCTION_TRACER
290	depends on DYNAMIC_FTRACE_WITH_REGS
291	depends on HAVE_RETHOOK
292	select RETHOOK
293	default n
294	help
295	  This option enables kernel function probe (fprobe) based on ftrace.
296	  The fprobe is similar to kprobes, but probes only for kernel function
297	  entries and exits. This also can probe multiple functions by one
298	  fprobe.
299
300	  If unsure, say N.
301
302config FUNCTION_PROFILER
303	bool "Kernel function profiler"
304	depends on FUNCTION_TRACER
305	default n
306	help
307	  This option enables the kernel function profiler. A file is created
308	  in debugfs called function_profile_enabled which defaults to zero.
309	  When a 1 is echoed into this file profiling begins, and when a
310	  zero is entered, profiling stops. A "functions" file is created in
311	  the trace_stat directory; this file shows the list of functions that
312	  have been hit and their counters.
313
314	  If in doubt, say N.
315
316config STACK_TRACER
317	bool "Trace max stack"
318	depends on HAVE_FUNCTION_TRACER
319	select FUNCTION_TRACER
320	select STACKTRACE
321	select KALLSYMS
322	help
323	  This special tracer records the maximum stack footprint of the
324	  kernel and displays it in /sys/kernel/tracing/stack_trace.
325
326	  This tracer works by hooking into every function call that the
327	  kernel executes, and keeping a maximum stack depth value and
328	  stack-trace saved.  If this is configured with DYNAMIC_FTRACE
329	  then it will not have any overhead while the stack tracer
330	  is disabled.
331
332	  To enable the stack tracer on bootup, pass in 'stacktrace'
333	  on the kernel command line.
334
335	  The stack tracer can also be enabled or disabled via the
336	  sysctl kernel.stack_tracer_enabled
337
338	  Say N if unsure.
339
340config TRACE_PREEMPT_TOGGLE
341	bool
342	help
343	  Enables hooks which will be called when preemption is first disabled,
344	  and last enabled.
345
346config IRQSOFF_TRACER
347	bool "Interrupts-off Latency Tracer"
348	default n
349	depends on TRACE_IRQFLAGS_SUPPORT
350	select TRACE_IRQFLAGS
351	select GENERIC_TRACER
352	select TRACER_MAX_TRACE
353	select RING_BUFFER_ALLOW_SWAP
354	select TRACER_SNAPSHOT
355	select TRACER_SNAPSHOT_PER_CPU_SWAP
356	help
357	  This option measures the time spent in irqs-off critical
358	  sections, with microsecond accuracy.
359
360	  The default measurement method is a maximum search, which is
361	  disabled by default and can be runtime (re-)started
362	  via:
363
364	      echo 0 > /sys/kernel/tracing/tracing_max_latency
365
366	  (Note that kernel size and overhead increase with this option
367	  enabled. This option and the preempt-off timing option can be
368	  used together or separately.)
369
370config PREEMPT_TRACER
371	bool "Preemption-off Latency Tracer"
372	default n
373	depends on PREEMPTION
374	select GENERIC_TRACER
375	select TRACER_MAX_TRACE
376	select RING_BUFFER_ALLOW_SWAP
377	select TRACER_SNAPSHOT
378	select TRACER_SNAPSHOT_PER_CPU_SWAP
379	select TRACE_PREEMPT_TOGGLE
380	help
381	  This option measures the time spent in preemption-off critical
382	  sections, with microsecond accuracy.
383
384	  The default measurement method is a maximum search, which is
385	  disabled by default and can be runtime (re-)started
386	  via:
387
388	      echo 0 > /sys/kernel/tracing/tracing_max_latency
389
390	  (Note that kernel size and overhead increase with this option
391	  enabled. This option and the irqs-off timing option can be
392	  used together or separately.)
393
394config SCHED_TRACER
395	bool "Scheduling Latency Tracer"
396	select GENERIC_TRACER
397	select CONTEXT_SWITCH_TRACER
398	select TRACER_MAX_TRACE
399	select TRACER_SNAPSHOT
400	help
401	  This tracer tracks the latency of the highest priority task
402	  to be scheduled in, starting from the point it has woken up.
403
404config HWLAT_TRACER
405	bool "Tracer to detect hardware latencies (like SMIs)"
406	select GENERIC_TRACER
407	select TRACER_MAX_TRACE
408	help
409	 This tracer, when enabled will create one or more kernel threads,
410	 depending on what the cpumask file is set to, which each thread
411	 spinning in a loop looking for interruptions caused by
412	 something other than the kernel. For example, if a
413	 System Management Interrupt (SMI) takes a noticeable amount of
414	 time, this tracer will detect it. This is useful for testing
415	 if a system is reliable for Real Time tasks.
416
417	 Some files are created in the tracing directory when this
418	 is enabled:
419
420	   hwlat_detector/width   - time in usecs for how long to spin for
421	   hwlat_detector/window  - time in usecs between the start of each
422				     iteration
423
424	 A kernel thread is created that will spin with interrupts disabled
425	 for "width" microseconds in every "window" cycle. It will not spin
426	 for "window - width" microseconds, where the system can
427	 continue to operate.
428
429	 The output will appear in the trace and trace_pipe files.
430
431	 When the tracer is not running, it has no affect on the system,
432	 but when it is running, it can cause the system to be
433	 periodically non responsive. Do not run this tracer on a
434	 production system.
435
436	 To enable this tracer, echo in "hwlat" into the current_tracer
437	 file. Every time a latency is greater than tracing_thresh, it will
438	 be recorded into the ring buffer.
439
440config OSNOISE_TRACER
441	bool "OS Noise tracer"
442	select GENERIC_TRACER
443	select TRACER_MAX_TRACE
444	help
445	  In the context of high-performance computing (HPC), the Operating
446	  System Noise (osnoise) refers to the interference experienced by an
447	  application due to activities inside the operating system. In the
448	  context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
449	  can cause noise to the system. Moreover, hardware-related jobs can
450	  also cause noise, for example, via SMIs.
451
452	  The osnoise tracer leverages the hwlat_detector by running a similar
453	  loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
454	  the sources of osnoise during its execution. The osnoise tracer takes
455	  note of the entry and exit point of any source of interferences,
456	  increasing a per-cpu interference counter. It saves an interference
457	  counter for each source of interference. The interference counter for
458	  NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
459	  observes these interferences' entry events. When a noise happens
460	  without any interference from the operating system level, the
461	  hardware noise counter increases, pointing to a hardware-related
462	  noise. In this way, osnoise can account for any source of
463	  interference. At the end of the period, the osnoise tracer prints
464	  the sum of all noise, the max single noise, the percentage of CPU
465	  available for the thread, and the counters for the noise sources.
466
467	  In addition to the tracer, a set of tracepoints were added to
468	  facilitate the identification of the osnoise source.
469
470	  The output will appear in the trace and trace_pipe files.
471
472	  To enable this tracer, echo in "osnoise" into the current_tracer
473          file.
474
475config TIMERLAT_TRACER
476	bool "Timerlat tracer"
477	select OSNOISE_TRACER
478	select GENERIC_TRACER
479	help
480	  The timerlat tracer aims to help the preemptive kernel developers
481	  to find sources of wakeup latencies of real-time threads.
482
483	  The tracer creates a per-cpu kernel thread with real-time priority.
484	  The tracer thread sets a periodic timer to wakeup itself, and goes
485	  to sleep waiting for the timer to fire. At the wakeup, the thread
486	  then computes a wakeup latency value as the difference between
487	  the current time and the absolute time that the timer was set
488	  to expire.
489
490	  The tracer prints two lines at every activation. The first is the
491	  timer latency observed at the hardirq context before the
492	  activation of the thread. The second is the timer latency observed
493	  by the thread, which is the same level that cyclictest reports. The
494	  ACTIVATION ID field serves to relate the irq execution to its
495	  respective thread execution.
496
497	  The tracer is build on top of osnoise tracer, and the osnoise:
498	  events can be used to trace the source of interference from NMI,
499	  IRQs and other threads. It also enables the capture of the
500	  stacktrace at the IRQ context, which helps to identify the code
501	  path that can cause thread delay.
502
503config MMIOTRACE
504	bool "Memory mapped IO tracing"
505	depends on HAVE_MMIOTRACE_SUPPORT && PCI
506	select GENERIC_TRACER
507	help
508	  Mmiotrace traces Memory Mapped I/O access and is meant for
509	  debugging and reverse engineering. It is called from the ioremap
510	  implementation and works via page faults. Tracing is disabled by
511	  default and can be enabled at run-time.
512
513	  See Documentation/trace/mmiotrace.rst.
514	  If you are not helping to develop drivers, say N.
515
516config ENABLE_DEFAULT_TRACERS
517	bool "Trace process context switches and events"
518	depends on !GENERIC_TRACER
519	select TRACING
520	help
521	  This tracer hooks to various trace points in the kernel,
522	  allowing the user to pick and choose which trace point they
523	  want to trace. It also includes the sched_switch tracer plugin.
524
525config FTRACE_SYSCALLS
526	bool "Trace syscalls"
527	depends on HAVE_SYSCALL_TRACEPOINTS
528	select GENERIC_TRACER
529	select KALLSYMS
530	help
531	  Basic tracer to catch the syscall entry and exit events.
532
533config TRACER_SNAPSHOT
534	bool "Create a snapshot trace buffer"
535	select TRACER_MAX_TRACE
536	help
537	  Allow tracing users to take snapshot of the current buffer using the
538	  ftrace interface, e.g.:
539
540	      echo 1 > /sys/kernel/tracing/snapshot
541	      cat snapshot
542
543config TRACER_SNAPSHOT_PER_CPU_SWAP
544	bool "Allow snapshot to swap per CPU"
545	depends on TRACER_SNAPSHOT
546	select RING_BUFFER_ALLOW_SWAP
547	help
548	  Allow doing a snapshot of a single CPU buffer instead of a
549	  full swap (all buffers). If this is set, then the following is
550	  allowed:
551
552	      echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
553
554	  After which, only the tracing buffer for CPU 2 was swapped with
555	  the main tracing buffer, and the other CPU buffers remain the same.
556
557	  When this is enabled, this adds a little more overhead to the
558	  trace recording, as it needs to add some checks to synchronize
559	  recording with swaps. But this does not affect the performance
560	  of the overall system. This is enabled by default when the preempt
561	  or irq latency tracers are enabled, as those need to swap as well
562	  and already adds the overhead (plus a lot more).
563
564config TRACE_BRANCH_PROFILING
565	bool
566	select GENERIC_TRACER
567
568choice
569	prompt "Branch Profiling"
570	default BRANCH_PROFILE_NONE
571	help
572	 The branch profiling is a software profiler. It will add hooks
573	 into the C conditionals to test which path a branch takes.
574
575	 The likely/unlikely profiler only looks at the conditions that
576	 are annotated with a likely or unlikely macro.
577
578	 The "all branch" profiler will profile every if-statement in the
579	 kernel. This profiler will also enable the likely/unlikely
580	 profiler.
581
582	 Either of the above profilers adds a bit of overhead to the system.
583	 If unsure, choose "No branch profiling".
584
585config BRANCH_PROFILE_NONE
586	bool "No branch profiling"
587	help
588	  No branch profiling. Branch profiling adds a bit of overhead.
589	  Only enable it if you want to analyse the branching behavior.
590	  Otherwise keep it disabled.
591
592config PROFILE_ANNOTATED_BRANCHES
593	bool "Trace likely/unlikely profiler"
594	select TRACE_BRANCH_PROFILING
595	help
596	  This tracer profiles all likely and unlikely macros
597	  in the kernel. It will display the results in:
598
599	  /sys/kernel/tracing/trace_stat/branch_annotated
600
601	  Note: this will add a significant overhead; only turn this
602	  on if you need to profile the system's use of these macros.
603
604config PROFILE_ALL_BRANCHES
605	bool "Profile all if conditionals" if !FORTIFY_SOURCE
606	select TRACE_BRANCH_PROFILING
607	help
608	  This tracer profiles all branch conditions. Every if ()
609	  taken in the kernel is recorded whether it hit or miss.
610	  The results will be displayed in:
611
612	  /sys/kernel/tracing/trace_stat/branch_all
613
614	  This option also enables the likely/unlikely profiler.
615
616	  This configuration, when enabled, will impose a great overhead
617	  on the system. This should only be enabled when the system
618	  is to be analyzed in much detail.
619endchoice
620
621config TRACING_BRANCHES
622	bool
623	help
624	  Selected by tracers that will trace the likely and unlikely
625	  conditions. This prevents the tracers themselves from being
626	  profiled. Profiling the tracing infrastructure can only happen
627	  when the likelys and unlikelys are not being traced.
628
629config BRANCH_TRACER
630	bool "Trace likely/unlikely instances"
631	depends on TRACE_BRANCH_PROFILING
632	select TRACING_BRANCHES
633	help
634	  This traces the events of likely and unlikely condition
635	  calls in the kernel.  The difference between this and the
636	  "Trace likely/unlikely profiler" is that this is not a
637	  histogram of the callers, but actually places the calling
638	  events into a running trace buffer to see when and where the
639	  events happened, as well as their results.
640
641	  Say N if unsure.
642
643config BLK_DEV_IO_TRACE
644	bool "Support for tracing block IO actions"
645	depends on SYSFS
646	depends on BLOCK
647	select RELAY
648	select DEBUG_FS
649	select TRACEPOINTS
650	select GENERIC_TRACER
651	select STACKTRACE
652	help
653	  Say Y here if you want to be able to trace the block layer actions
654	  on a given queue. Tracing allows you to see any traffic happening
655	  on a block device queue. For more information (and the userspace
656	  support tools needed), fetch the blktrace tools from:
657
658	  git://git.kernel.dk/blktrace.git
659
660	  Tracing also is possible using the ftrace interface, e.g.:
661
662	    echo 1 > /sys/block/sda/sda1/trace/enable
663	    echo blk > /sys/kernel/tracing/current_tracer
664	    cat /sys/kernel/tracing/trace_pipe
665
666	  If unsure, say N.
667
668config FPROBE_EVENTS
669	depends on FPROBE
670	depends on HAVE_REGS_AND_STACK_ACCESS_API
671	bool "Enable fprobe-based dynamic events"
672	select TRACING
673	select PROBE_EVENTS
674	select DYNAMIC_EVENTS
675	default y
676	help
677	  This allows user to add tracing events on the function entry and
678	  exit via ftrace interface. The syntax is same as the kprobe events
679	  and the kprobe events on function entry and exit will be
680	  transparently converted to this fprobe events.
681
682config PROBE_EVENTS_BTF_ARGS
683	depends on HAVE_FUNCTION_ARG_ACCESS_API
684	depends on FPROBE_EVENTS || KPROBE_EVENTS
685	depends on DEBUG_INFO_BTF && BPF_SYSCALL
686	bool "Support BTF function arguments for probe events"
687	default y
688	help
689	  The user can specify the arguments of the probe event using the names
690	  of the arguments of the probed function, when the probe location is a
691	  kernel function entry or a tracepoint.
692	  This is available only if BTF (BPF Type Format) support is enabled.
693
694config KPROBE_EVENTS
695	depends on KPROBES
696	depends on HAVE_REGS_AND_STACK_ACCESS_API
697	bool "Enable kprobes-based dynamic events"
698	select TRACING
699	select PROBE_EVENTS
700	select DYNAMIC_EVENTS
701	default y
702	help
703	  This allows the user to add tracing events (similar to tracepoints)
704	  on the fly via the ftrace interface. See
705	  Documentation/trace/kprobetrace.rst for more details.
706
707	  Those events can be inserted wherever kprobes can probe, and record
708	  various register and memory values.
709
710	  This option is also required by perf-probe subcommand of perf tools.
711	  If you want to use perf tools, this option is strongly recommended.
712
713config KPROBE_EVENTS_ON_NOTRACE
714	bool "Do NOT protect notrace function from kprobe events"
715	depends on KPROBE_EVENTS
716	depends on DYNAMIC_FTRACE
717	default n
718	help
719	  This is only for the developers who want to debug ftrace itself
720	  using kprobe events.
721
722	  If kprobes can use ftrace instead of breakpoint, ftrace related
723	  functions are protected from kprobe-events to prevent an infinite
724	  recursion or any unexpected execution path which leads to a kernel
725	  crash.
726
727	  This option disables such protection and allows you to put kprobe
728	  events on ftrace functions for debugging ftrace by itself.
729	  Note that this might let you shoot yourself in the foot.
730
731	  If unsure, say N.
732
733config UPROBE_EVENTS
734	bool "Enable uprobes-based dynamic events"
735	depends on ARCH_SUPPORTS_UPROBES
736	depends on MMU
737	depends on PERF_EVENTS
738	select UPROBES
739	select PROBE_EVENTS
740	select DYNAMIC_EVENTS
741	select TRACING
742	default y
743	help
744	  This allows the user to add tracing events on top of userspace
745	  dynamic events (similar to tracepoints) on the fly via the trace
746	  events interface. Those events can be inserted wherever uprobes
747	  can probe, and record various registers.
748	  This option is required if you plan to use perf-probe subcommand
749	  of perf tools on user space applications.
750
751config BPF_EVENTS
752	depends on BPF_SYSCALL
753	depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
754	bool
755	default y
756	help
757	  This allows the user to attach BPF programs to kprobe, uprobe, and
758	  tracepoint events.
759
760config DYNAMIC_EVENTS
761	def_bool n
762
763config PROBE_EVENTS
764	def_bool n
765
766config BPF_KPROBE_OVERRIDE
767	bool "Enable BPF programs to override a kprobed function"
768	depends on BPF_EVENTS
769	depends on FUNCTION_ERROR_INJECTION
770	default n
771	help
772	 Allows BPF to override the execution of a probed function and
773	 set a different return value.  This is used for error injection.
774
775config FTRACE_MCOUNT_RECORD
776	def_bool y
777	depends on DYNAMIC_FTRACE
778	depends on HAVE_FTRACE_MCOUNT_RECORD
779
780config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
781	bool
782	depends on FTRACE_MCOUNT_RECORD
783
784config FTRACE_MCOUNT_USE_CC
785	def_bool y
786	depends on $(cc-option,-mrecord-mcount)
787	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
788	depends on FTRACE_MCOUNT_RECORD
789
790config FTRACE_MCOUNT_USE_OBJTOOL
791	def_bool y
792	depends on HAVE_OBJTOOL_MCOUNT
793	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
794	depends on !FTRACE_MCOUNT_USE_CC
795	depends on FTRACE_MCOUNT_RECORD
796	select OBJTOOL
797
798config FTRACE_MCOUNT_USE_RECORDMCOUNT
799	def_bool y
800	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
801	depends on !FTRACE_MCOUNT_USE_CC
802	depends on !FTRACE_MCOUNT_USE_OBJTOOL
803	depends on FTRACE_MCOUNT_RECORD
804
805config TRACING_MAP
806	bool
807	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
808	help
809	  tracing_map is a special-purpose lock-free map for tracing,
810	  separated out as a stand-alone facility in order to allow it
811	  to be shared between multiple tracers.  It isn't meant to be
812	  generally used outside of that context, and is normally
813	  selected by tracers that use it.
814
815config SYNTH_EVENTS
816	bool "Synthetic trace events"
817	select TRACING
818	select DYNAMIC_EVENTS
819	default n
820	help
821	  Synthetic events are user-defined trace events that can be
822	  used to combine data from other trace events or in fact any
823	  data source.  Synthetic events can be generated indirectly
824	  via the trace() action of histogram triggers or directly
825	  by way of an in-kernel API.
826
827	  See Documentation/trace/events.rst or
828	  Documentation/trace/histogram.rst for details and examples.
829
830	  If in doubt, say N.
831
832config USER_EVENTS
833	bool "User trace events"
834	select TRACING
835	select DYNAMIC_EVENTS
836	help
837	  User trace events are user-defined trace events that
838	  can be used like an existing kernel trace event.  User trace
839	  events are generated by writing to a tracefs file.  User
840	  processes can determine if their tracing events should be
841	  generated by registering a value and bit with the kernel
842	  that reflects when it is enabled or not.
843
844	  See Documentation/trace/user_events.rst.
845	  If in doubt, say N.
846
847config HIST_TRIGGERS
848	bool "Histogram triggers"
849	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
850	select TRACING_MAP
851	select TRACING
852	select DYNAMIC_EVENTS
853	select SYNTH_EVENTS
854	default n
855	help
856	  Hist triggers allow one or more arbitrary trace event fields
857	  to be aggregated into hash tables and dumped to stdout by
858	  reading a debugfs/tracefs file.  They're useful for
859	  gathering quick and dirty (though precise) summaries of
860	  event activity as an initial guide for further investigation
861	  using more advanced tools.
862
863	  Inter-event tracing of quantities such as latencies is also
864	  supported using hist triggers under this option.
865
866	  See Documentation/trace/histogram.rst.
867	  If in doubt, say N.
868
869config TRACE_EVENT_INJECT
870	bool "Trace event injection"
871	depends on TRACING
872	help
873	  Allow user-space to inject a specific trace event into the ring
874	  buffer. This is mainly used for testing purpose.
875
876	  If unsure, say N.
877
878config TRACEPOINT_BENCHMARK
879	bool "Add tracepoint that benchmarks tracepoints"
880	help
881	 This option creates the tracepoint "benchmark:benchmark_event".
882	 When the tracepoint is enabled, it kicks off a kernel thread that
883	 goes into an infinite loop (calling cond_resched() to let other tasks
884	 run), and calls the tracepoint. Each iteration will record the time
885	 it took to write to the tracepoint and the next iteration that
886	 data will be passed to the tracepoint itself. That is, the tracepoint
887	 will report the time it took to do the previous tracepoint.
888	 The string written to the tracepoint is a static string of 128 bytes
889	 to keep the time the same. The initial string is simply a write of
890	 "START". The second string records the cold cache time of the first
891	 write which is not added to the rest of the calculations.
892
893	 As it is a tight loop, it benchmarks as hot cache. That's fine because
894	 we care most about hot paths that are probably in cache already.
895
896	 An example of the output:
897
898	      START
899	      first=3672 [COLD CACHED]
900	      last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
901	      last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
902	      last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
903	      last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
904	      last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
905	      last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
906
907
908config RING_BUFFER_BENCHMARK
909	tristate "Ring buffer benchmark stress tester"
910	depends on RING_BUFFER
911	help
912	  This option creates a test to stress the ring buffer and benchmark it.
913	  It creates its own ring buffer such that it will not interfere with
914	  any other users of the ring buffer (such as ftrace). It then creates
915	  a producer and consumer that will run for 10 seconds and sleep for
916	  10 seconds. Each interval it will print out the number of events
917	  it recorded and give a rough estimate of how long each iteration took.
918
919	  It does not disable interrupts or raise its priority, so it may be
920	  affected by processes that are running.
921
922	  If unsure, say N.
923
924config TRACE_EVAL_MAP_FILE
925       bool "Show eval mappings for trace events"
926       depends on TRACING
927       help
928	The "print fmt" of the trace events will show the enum/sizeof names
929	instead of their values. This can cause problems for user space tools
930	that use this string to parse the raw data as user space does not know
931	how to convert the string to its value.
932
933	To fix this, there's a special macro in the kernel that can be used
934	to convert an enum/sizeof into its value. If this macro is used, then
935	the print fmt strings will be converted to their values.
936
937	If something does not get converted properly, this option can be
938	used to show what enums/sizeof the kernel tried to convert.
939
940	This option is for debugging the conversions. A file is created
941	in the tracing directory called "eval_map" that will show the
942	names matched with their values and what trace event system they
943	belong too.
944
945	Normally, the mapping of the strings to values will be freed after
946	boot up or module load. With this option, they will not be freed, as
947	they are needed for the "eval_map" file. Enabling this option will
948	increase the memory footprint of the running kernel.
949
950	If unsure, say N.
951
952config FTRACE_RECORD_RECURSION
953	bool "Record functions that recurse in function tracing"
954	depends on FUNCTION_TRACER
955	help
956	  All callbacks that attach to the function tracing have some sort
957	  of protection against recursion. Even though the protection exists,
958	  it adds overhead. This option will create a file in the tracefs
959	  file system called "recursed_functions" that will list the functions
960	  that triggered a recursion.
961
962	  This will add more overhead to cases that have recursion.
963
964	  If unsure, say N
965
966config FTRACE_RECORD_RECURSION_SIZE
967	int "Max number of recursed functions to record"
968	default	128
969	depends on FTRACE_RECORD_RECURSION
970	help
971	  This defines the limit of number of functions that can be
972	  listed in the "recursed_functions" file, that lists all
973	  the functions that caused a recursion to happen.
974	  This file can be reset, but the limit can not change in
975	  size at runtime.
976
977config RING_BUFFER_RECORD_RECURSION
978	bool "Record functions that recurse in the ring buffer"
979	depends on FTRACE_RECORD_RECURSION
980	# default y, because it is coupled with FTRACE_RECORD_RECURSION
981	default y
982	help
983	  The ring buffer has its own internal recursion. Although when
984	  recursion happens it won't cause harm because of the protection,
985	  but it does cause unwanted overhead. Enabling this option will
986	  place where recursion was detected into the ftrace "recursed_functions"
987	  file.
988
989	  This will add more overhead to cases that have recursion.
990
991config GCOV_PROFILE_FTRACE
992	bool "Enable GCOV profiling on ftrace subsystem"
993	depends on GCOV_KERNEL
994	help
995	  Enable GCOV profiling on ftrace subsystem for checking
996	  which functions/lines are tested.
997
998	  If unsure, say N.
999
1000	  Note that on a kernel compiled with this config, ftrace will
1001	  run significantly slower.
1002
1003config FTRACE_SELFTEST
1004	bool
1005
1006config FTRACE_STARTUP_TEST
1007	bool "Perform a startup test on ftrace"
1008	depends on GENERIC_TRACER
1009	select FTRACE_SELFTEST
1010	help
1011	  This option performs a series of startup tests on ftrace. On bootup
1012	  a series of tests are made to verify that the tracer is
1013	  functioning properly. It will do tests on all the configured
1014	  tracers of ftrace.
1015
1016config EVENT_TRACE_STARTUP_TEST
1017	bool "Run selftest on trace events"
1018	depends on FTRACE_STARTUP_TEST
1019	default y
1020	help
1021	  This option performs a test on all trace events in the system.
1022	  It basically just enables each event and runs some code that
1023	  will trigger events (not necessarily the event it enables)
1024	  This may take some time run as there are a lot of events.
1025
1026config EVENT_TRACE_TEST_SYSCALLS
1027	bool "Run selftest on syscall events"
1028	depends on EVENT_TRACE_STARTUP_TEST
1029	help
1030	 This option will also enable testing every syscall event.
1031	 It only enables the event and disables it and runs various loads
1032	 with the event enabled. This adds a bit more time for kernel boot
1033	 up since it runs this on every system call defined.
1034
1035	 TBD - enable a way to actually call the syscalls as we test their
1036	       events
1037
1038config FTRACE_SORT_STARTUP_TEST
1039       bool "Verify compile time sorting of ftrace functions"
1040       depends on DYNAMIC_FTRACE
1041       depends on BUILDTIME_MCOUNT_SORT
1042       help
1043	 Sorting of the mcount_loc sections that is used to find the
1044	 where the ftrace knows where to patch functions for tracing
1045	 and other callbacks is done at compile time. But if the sort
1046	 is not done correctly, it will cause non-deterministic failures.
1047	 When this is set, the sorted sections will be verified that they
1048	 are in deed sorted and will warn if they are not.
1049
1050	 If unsure, say N
1051
1052config RING_BUFFER_STARTUP_TEST
1053       bool "Ring buffer startup self test"
1054       depends on RING_BUFFER
1055       help
1056	 Run a simple self test on the ring buffer on boot up. Late in the
1057	 kernel boot sequence, the test will start that kicks off
1058	 a thread per cpu. Each thread will write various size events
1059	 into the ring buffer. Another thread is created to send IPIs
1060	 to each of the threads, where the IPI handler will also write
1061	 to the ring buffer, to test/stress the nesting ability.
1062	 If any anomalies are discovered, a warning will be displayed
1063	 and all ring buffers will be disabled.
1064
1065	 The test runs for 10 seconds. This will slow your boot time
1066	 by at least 10 more seconds.
1067
1068	 At the end of the test, statistics and more checks are done.
1069	 It will output the stats of each per cpu buffer: What
1070	 was written, the sizes, what was read, what was lost, and
1071	 other similar details.
1072
1073	 If unsure, say N
1074
1075config RING_BUFFER_VALIDATE_TIME_DELTAS
1076	bool "Verify ring buffer time stamp deltas"
1077	depends on RING_BUFFER
1078	help
1079	  This will audit the time stamps on the ring buffer sub
1080	  buffer to make sure that all the time deltas for the
1081	  events on a sub buffer matches the current time stamp.
1082	  This audit is performed for every event that is not
1083	  interrupted, or interrupting another event. A check
1084	  is also made when traversing sub buffers to make sure
1085	  that all the deltas on the previous sub buffer do not
1086	  add up to be greater than the current time stamp.
1087
1088	  NOTE: This adds significant overhead to recording of events,
1089	  and should only be used to test the logic of the ring buffer.
1090	  Do not use it on production systems.
1091
1092	  Only say Y if you understand what this does, and you
1093	  still want it enabled. Otherwise say N
1094
1095config MMIOTRACE_TEST
1096	tristate "Test module for mmiotrace"
1097	depends on MMIOTRACE && m
1098	help
1099	  This is a dumb module for testing mmiotrace. It is very dangerous
1100	  as it will write garbage to IO memory starting at a given address.
1101	  However, it should be safe to use on e.g. unused portion of VRAM.
1102
1103	  Say N, unless you absolutely know what you are doing.
1104
1105config PREEMPTIRQ_DELAY_TEST
1106	tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1107	depends on m
1108	help
1109	  Select this option to build a test module that can help test latency
1110	  tracers by executing a preempt or irq disable section with a user
1111	  configurable delay. The module busy waits for the duration of the
1112	  critical section.
1113
1114	  For example, the following invocation generates a burst of three
1115	  irq-disabled critical sections for 500us:
1116	  modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
1117
1118	  What's more, if you want to attach the test on the cpu which the latency
1119	  tracer is running on, specify cpu_affinity=cpu_num at the end of the
1120	  command.
1121
1122	  If unsure, say N
1123
1124config SYNTH_EVENT_GEN_TEST
1125	tristate "Test module for in-kernel synthetic event generation"
1126	depends on SYNTH_EVENTS
1127	help
1128          This option creates a test module to check the base
1129          functionality of in-kernel synthetic event definition and
1130          generation.
1131
1132          To test, insert the module, and then check the trace buffer
1133	  for the generated sample events.
1134
1135	  If unsure, say N.
1136
1137config KPROBE_EVENT_GEN_TEST
1138	tristate "Test module for in-kernel kprobe event generation"
1139	depends on KPROBE_EVENTS
1140	help
1141          This option creates a test module to check the base
1142          functionality of in-kernel kprobe event definition.
1143
1144          To test, insert the module, and then check the trace buffer
1145	  for the generated kprobe events.
1146
1147	  If unsure, say N.
1148
1149config HIST_TRIGGERS_DEBUG
1150	bool "Hist trigger debug support"
1151	depends on HIST_TRIGGERS
1152	help
1153          Add "hist_debug" file for each event, which when read will
1154          dump out a bunch of internal details about the hist triggers
1155          defined on that event.
1156
1157          The hist_debug file serves a couple of purposes:
1158
1159            - Helps developers verify that nothing is broken.
1160
1161            - Provides educational information to support the details
1162              of the hist trigger internals as described by
1163              Documentation/trace/histogram-design.rst.
1164
1165          The hist_debug output only covers the data structures
1166          related to the histogram definitions themselves and doesn't
1167          display the internals of map buckets or variable values of
1168          running histograms.
1169
1170          If unsure, say N.
1171
1172source "kernel/trace/rv/Kconfig"
1173
1174endif # FTRACE
1175